Theoretical concepts of operation of a semiconductor detector based on a p-n junction

Collected charge originating in a semiconductor detector of the p+-n-n+ type as a result of interaction with a monoenergetic electron beam with energies in the range from 7 to 25 keV is calculated. Generation of electron-hole pairs (EHPs) is calculated using the Monte Carlo method. In the context of the diffusion-drift model, an analytic expression for the contribution of generated EHPs to the detected signal is derived. It is shown that the losses of charge to recombination in the course of transport significantly affect the shape of detected signal. The comparison of simulated energy spectra with experimentally measured spectra shows good agreement between theory and experiment. Thus, the basics of a theoretical approach that makes it possible to calculate the operational characteristics of semiconductor detectors are developed; as a result, the parameters of these detectors can be optimized in designing the practically important semiconductor proportional detectors to be used in analytical methods.